The invention relates generally to systems for processing optical data, and more particularly to an optical correlator for providing quantitative data on image reduction of random fields.
Motion pictures are extremely useful in obtaining information on behaviour of flow fields such as generated within a wind tunnel, propulsion system, spray, or other turbulent flow system, and which characterizes deflagrating surfaces of combusting systems. A photograph presents substantial detailed information and therefore, reduction of data contained in a movie presents a formidable data reduction problem. This problem has substantially limited the use of movies to a qualitative visual understanding of the phenomena under study. A need therefore exists for a system for reducing images of substantially quasirandom fields to quantitative data.
In the quantitative analysis of images of random fields, such as that of deflagrating solid rocket propellant surfaces, digital computer systems are generally not suitable, since digital systems handle only digital data and process data serially and relatively slowly. In particular, image analysis by a digital system requires point-by-point analog-to-digital (A/D) conversion and serial operations; the light output of the image must first be converted into digital numbers and stored, and this process repetitively performed to cover the entire image. Since the detail of a single motion picture frame may exceed 10.sup.6 pixels, the memory store for a multiplicity of frames comprising a movie is large, which may preclude use of digital analysis for data reduction of random fields.
The present invention provides an optical correlator for quantitative analysis of images of random flow fields such as those mentioned above. The invention comprises an analog optical data processing system including a series of lenses to perform optical operations on random field images under examination, and allow the examination of an entire image at once, i.e., performs parallel data processing by mapping one two dimensional data field onto another simultaneously. The correlator is simple and economical in structure and operation and has extremely fast response time, especially in data reduction of photographs or movies. A quantitative description of the correlation function of a random flow field image may be conveniently obtained.
It is therefore a principal object of the invention to provide an improved optical data correlator.
It is a further object of the invention to provide an optical data correlator for quantitative analysis of random field images.
It is another object to procide an optical data correlator for analysis of combustion systems and other turbulent flow systems.
These and other objects of the invention will become apparent as the detailed description of representative embodiments proceeds.